About a year or so ago, I was presented with a Philips transistor radio that according to the owner had been struck by lightning. Fortunately, the lightning strike must have been quite some distance...

“The velocity factor (VF), also called wave propagation speed or velocity of propagation, of a transmission medium, is the speed at which a wavefront (of an acoustic signal, for example, or an electromagnetic signal,...

Multimeters measure electrical quantities, and will at the very least measure Voltage, Resistance and Current. Usually they will have an AC and DC range. A multimeter is an essential item in any hobby electronics...